I've partied with several hypnodommes and dated one. Your options for meeting them are somewhat limited for the most part. If you're near a city, a reliable start is by attending in-person hypno events and parties (there are several on FetLife, etc). Don't expect anything to happen - just hang out and socialize with people at first. People will ask you for play if you seem cool to hang out with. Maybe something more develops. Your odds go up if you become an established positive influence in their social groups.
Your other (probably more accessible) avenue is to hang out in broader communities that are kink-adjacent or generally open-minded (especially people who might already have some affinity to roleplay, such as gamers, Renaissance Faire attendees, goth clubs, etc). Meet people, have a good time, and maybe you'll meet somebody who seems like a top personality. Once you get a few dates in, you can try testing the waters a bit by commenting on hypno references in shows or just joking about it casually. The people who tend to react positively are often curious/playful by nature. If you're really comfortable and want to shoot your shot, you could just be like "somebody posted this hypnosis recording online that's supposed to make me [something fun, like have an insatiable need to go down on her], should I do it?"